Furnace for burning pulverized fuel.



Patented Apr. 9, 1918. I 2 SHEETS-SHEET I.

J. E. MUHLFELD. FURNACE FOR BURNING PULVERIZED FUEL.

APPLICATION FILED DEC. 2. 1913.

WITNESS S J. E. MUHLF ELD. FURNACE FOR BURNING PULVERIZED FUELQAPPLICATION FILED DEC- 2, '93 1,262,546., Patented Apr. 9,1918.

I 2 SHEETS-SHEET 2 wrmzss s ina-ry sore? E. @1 SGABSDALE, NEW YGBK,ASSIG-NQR tilt) LGOEEGTEVE EULVEBEZED FUEL CQMPANY, A CORPQRATION @175IBELAWVAEE,

FU'Eblilfifil FOB BURNING PULVERIZ'ED ZFYUIEL.

recast-c,

Specification of letters Patent.

Patented Apr, 29,

Application filled EBecember 2, 1913. Serial No. 804,192.

To all whom it may conceive:

Be it known that 1, Joan lvlonnrnnn, of Scarsdale, in the county ofWestchester and S'tete of New York, have invented a certain new anduseful Improvement in Furnaces for Burning Pulveriaed Fuel, of whichimprovement the tollovving is a specification.

My invention, relates more particularly to means for burning combustiblematter in a comminuted or finely pulverized state, in the fireboxes orsteam boilers, particularly locomotive boilers, and in connection vvit'heating furnaces out other descriptions, and its object is to rovidemeans which shall be readily and inexpensively applicable in connectionwith furnaces or fireboxes of the ordinary construction, for supplyingfuel of such character and air, in proper proportions, to a furnace, andenabling its thorough and efi'ective combustion to be carried ontherein. I

To this end, my invention, generally stated, consists in thecombination, With a main orlfinal furnace chamber, of a prelimiurnacechamber, located vexterior and adjacent to the final furnace chamber andcommunicating therewith, and constituting a preliminary fuel treatmentspace, in which the fuel is commingled with air and gasified orpartially consumed prior to its complete combustion in the final furnacechamber.

The improvement claimed is hereinafter fully set forth.

In the accompanyln dravvincs: Figure l is a vertical .longitu inalcentral section through a locomotive boiler firebox, illustrating anapplication of invention; Fig. 2, a horizontal section through thepreliminaryfurncce chamber, on the line a o of Fig. 1; Fig. 1%, asection, taken similarly to Fin. 1, illustrating a structural modifica-=tion; big. 4:, a nertial horizontal section, on the line b b of Fig, 3;and, 5, a section, taken similarly to Figs it and 3, illustratinganother structural modification.

Referring first to'l igs. 1 and :2, my invention is exemplified asapplied in connection with a main or final furnace chamber, which isshown as a locomotive boiler firebox of one of the present standardtypes, and is indicated, as an entiretby the symbol A, from which c'amber the products or a plate or plates,

combustion of fuel burned therein are'conveyed through a plurality offire tubes, B, in the Waist, C, of the boiler, to a smoke box and stack,(not shown) at its opposite end, in the ordinary manner, in which theparts enumerated cooperate to produce a draft'in the firebox. I

In the practice of my invention, l provide, at the bottom of thefirebox, afloor, l, of brick or other suitable refractory material, theordinary rates and ash pan which are used for burnmg solid fuel notbeing necessary or applicable. The floor may be located at any desiredlevel, relatively to the bottom of the firebox, as may be best suited tothe depth of the latter, being herein shown as set some distance belovvthe mud ring, a, upwardly extending side and end Walls, 1, of. firebrick, forming a closure for the intervening space. lln fircbores ofgreater depth it may lie in or near the plane of the bottom of the mudrin A preliminary chamber, 2, of tire brick or other suitable refractorymaterial, props erly supported exterior and adjacent to the finalfurnace chamber or'firebon, A, being, in this instance, located belowthe mud ring, and extending rearwardly and horizontally from the backhead of the boiler, The "form, in transverse section, of the preliminarychamber, is not an essential of my invention,

and it may be or" rectangular, circular or elliptical transversesection, as preferred, bein in this particular instance, variable withinthe discretion of the constructor, or as may be best suited toacconnnodate ad3a= cent members of the vlocomotive on which it isinstalled; The preliminary chamber "is open at its front end to thefirebox, belowthe mud ring, either partially, as shown, or throughoutits full Width. 7

Bodies or columns of pulverized fuel are delivered into the rear end ofthe prelim inary chamber, 52, either by being forced thereinto bya tanor pressure blower, .orby

being drawn thereirto' by induced draft,

through one or more conduits, 23, any desired number of which may beapplied, and one being shown in Fig. 2. The conduit or conduits, 3, isorare passed through an o ening or openings, 3, which may be close by8?, in the rear wall of preliminary chambers-and are adapted for tillice

the introduction at a proper volninc cc throughthe tire door opening,

with. the fuel. The top, side, and rearwalls of the preliminary chamberare covered by layers, 4, of a material which is a non-conductor ofheat,the non-conductingcovering 5 being inclose'd in a casing, '4 of sheet orplate metal.

A slag receptacle, 5, which is open at its top to the fire box, issuspended below the floor, 1, thereof, at its rear end, and is pro- '10vided with an air inlet, 5, controlled by a door, 5 through which aregulated supply of. air ,may be admitted to the firebox.

In the operation of afurnace in connection with which a preliminarychamber substantiallyras, above described, is applied, the mix ture ofpulverized fuel and air which is delivered, through the conduit, 8, tothe preliminary chamber, 2, is commingled, in proper proportions, withair, ignited, and its preliminary combustion effected therein, it beingpartially consumed or gasified in said chamber, and the gaseous productsof com bustion passing therefrom into the main or final furnace chamber,A, in which complete combustion is efiected. The preliminary chamberbecomes highly heated, and the fuel and air supplied thereto are thor-\.ouglily commingled and preheated beforebeing completely consumed inthe final furnace chamber.

The structural modification shown in Figs.

5? and r is more particularly designed for application in connectionwith deep and narrow fireboxes, and while according in operativeprinciple with that first described,

difiers structurally therefrom, in the particular that the preliminarychamber, 2, is located above the level of the bottom of the finalfurnace chamber, A, and communicates therewith through the fire dooropening, 5, through which the products of combustion are delivered intothe final furnace chamber. Three fuel supply conduits, 3, are showniasleading into the preliminary cham- 4 her, their outlets converging inthe\direc tion of the discharge opening, 6, thereof, but one or. agreater number may be applied as may be considered preferable understruc tural. and operative conditions,

Fig. 5 illustrates another structural modification innwhich twopreliminary chambers, 2, and 2 applied in connection with the main orfinal furnace chamber, A, one of them,,2 being located above, and theother,

5 2, below, the firing deck of the locomotive, and being preferably, asshown, connected,

adjacentto the final furnace chamber, by a conduit, c, of refractorymaterial, one or more of which may be used as desired. The to lowerpreliminary chamber is open at its front end-to theifinal furnacechamber, as inthe instance first described, and shown-in Figs. land 2,and the upper chambercomreunieates with the final furn ce-chambernaeaeee and 4. As in the preceding cases, any de sired number of fuelsupply conduits may be @final furnace chamber or furnace proper in whichcomplete combustion is effected, so is rendered available for theburning of the fuel and gases. A feature of special advantag is thataofeconomy of construction, as the preliminary chamber may be,applied,-

as a separate structure, in connection with existing furnaces, atmaterially less cost than that of reconstructing and enlarging the mainfurnace.

It will be observed that the preliminary chamber in the arrangementshown in the drawings has the fuel supplied thereto through a nozzlewhich directs the fuel to ward the opening between the preliminarychamber and the firebox, this belngthe pre ferred construction becausethe travel of the fuel carried along by the gaseous medium through saidpreliminary chamber may then enter the firebox without seriousobstruction such as might precipitate some of the pulverized material.By making the preliminary chamber as shown of small crosssoctionalcapacity in relation to the size of the firebox or combustion space intowhich it opens, the flow through the preliminary chamber will berelatively more rapid help ing to hold the fuel in suspension and thenwhen it reaches the larger area of the combustioh space or firebox itsflow or velocity will be retarded so that the air supplied for finalcombustion will have better opportunity to become cdmmingled with thefuel and more complete cembustion andefticient operation will beobtained. The Velocity of flow through the preliminary chamber willvary, of course, with the dimensions of 11 the same so that ifit madeof. substantially less cross-sectional area, it operate primarily as amining or fuel treatment space for obtainin ther -such commingling ofthe air and fuel, latvinp the combustion to be accomplished in thefirebox itself l claim as my inventicn and desire to secure by LettersPatent:

l. in an apparatus for feeding and burn- 125, ing pulverized fuel, thecombination of a main furnace chamber, two preliminary treatmentchambers located exteriorly of and adjacent to the furnace chamber andat ends we with said main furnace chamber, means for admitting a mixtureof air and fuel to the rear ends of said preliminary treatment chambers,and a gas conduit connecting said preliminary treatment chambers at apoint intermediate their res ective extremities.

2 In an apparatus or feeding and burning pulverized fuel, thecombination of a main furnace chamber, a preliminary treatment chamberhaving communication at its forward end with the main furnace chamber, aplurality of openings at the rear end of said preliminary treatmentchamber, means for supplying amixture of fuel and air under pressurethrough each of said openings, the currents of fuel and air beingdirected to converge and intermix at the point of communication betweenthe said preliminary treatment chamber and the main furnace chamber.

3. A pulverized fuel burning apparatus comprising in combinationa meansof relatively small capacity for introducing pulverized fuel, apreliminary expansion chamber into which thefuel is introduced, andwhich is provided with means for admitting air at the place where thefuel is admitted, and in which the fuel is preliminarily mixed andtreated, said preliminary chamber being also provided wlth an outlet,and a relatively large combustion chamber into which the said outlet ofthe preliminary chamber opens, said combustion chamber being providedwith a waste outlet in its bottom and with an exhaust meanscommunicating with the upper part thereof.

l. A pulverized fuel comprising in combination a means of relativelysmall capacity for introducing a mixture of pulverized fuel and air, apreliminary expansion chamber into which the mixture of fuel and air isintroduced and which is provided with means for admittin additional airat the lace where'the fue is admitted and in which the fuel ispreliminarily mixed and treated, said preliminary cham ber being alsoprovided with an outlet, and a-relatively large combustion chamber intoburning apparatus which said outlet opens, said combustion chamberhaving means for admitting additional air therein, and a waste outlet atthe bottom thereof and means communicating with the upper part of thechamber for inducing a draft therein.

5. In an apparatus for feeding and burning pulverized fuel insuspension, the combination with a firing chamber and means for inducingdraft therein and a preliminary treatment chamber communicating withsaid firing chamber, of means for introducing a mixture of the fuel anda combustion supporting vehicle into said treatment chamber and forsimultaneously inducing atmospheric air therein in volumes substantiallyproportionate to the quantities of the mixture delivered butinsuflicient to effect complete combustion. and means whereby the draftin the firing chamber induces additional quantities of atmospheric airchamber, the point of inlet in the firing chamber being adjacent to theend of the preliminary chamber.

6. A pulverized fuel burning apparatus comprising the combination with asteam boiler, a firing chamber therefor having a waste outlet in thebottom and means forward of the chamber and communicating with the upperpart thereof for creating a draft to draw the gases of combustionthrough the firing chamber, of a preliminary treatment chamber having anoutlet opening into the firing chamber, means for introducing a mixtureof fuel and air into said treatment chamber, an opening near the samewhereby the fiow of an additional. supply of a combustion supportingmedium is drawn into the preliminary treatment chamber and added to saidmixture as it enters said chamber, but in quantities insufficient toeffect complete combustion, and means for admitting an additional supplyof air into the firing chamber.

JOHN E. MUHLFELD. Witnesses:

EMiLY L. MYERS, W. H. CoYLE.

into said firing

